This is a cross-sectional study examining behavioral and neurophysiologic changes associated with learning Mandarin Chinese as a second language (L2) by native English-speaking adult learners (ages 18 years and up). It will focus on the acquisition of lexical tones, which are pitch patterns that are used to contrast word meaning in Mandarin, and is not a linguistic feature of English. At the behavioral level, various studies investigating the learning of isolated non-native consonants in non-lexical and non-communicative contexts show that with the appropriate form and degree of training, adults can learn to perceive and/or produce sounds that do not occur in their native language. However, there have been few studies that investigated the learning of lexical tones or suprasegmentals, and fewer yet that considered the use of these non-native sounds in actual communicative contexts such as words. In recent years, several studies examined neural changes associated with speech and word learning; but they are either confined to laboratory training of speech sounds, or the learning of words without considering the contribution of phonetic features, especially suprasegmentals. While cross-linguistic research has been done comparing behavioral and neurophysiologic responses of native Mandarin-speaking and native English-speaking adults perceiving Mandarin tones, none was conducted to describe changes in non-Mandarin (English) speaking subjects as they become proficient in Mandarin. The current study will involve behavioral and fMRI experiments on university students learning Mandarin Chinese at four different stages (years 1 to 4 of the university curriculum). The general hypothesis is that increased L2 proficiency will result in behavioral and neurophysiologic responses closer to those in native speakers. An understanding of language development is important for developing the most efficacious language rehabilitation programs in cases of injuries such as strokes. For the rehabilitation of adults, it is especially important to understand how adults learn. [unreadable] [unreadable] [unreadable]